Devices are known which turn flat articles, such as letter envelopes, within a plane. These devices are required where envelopes are discharged from an inserter and are not properly oriented to be fed to a downstream device such as a franking machine. An inserter is a machine that places selected items in an envelope for further processing. The filled and sealed envelope is then conveyed to a franking machine to have postage imprinted thereon. Generally, turner devices have the disadvantage of not only having to turn the envelope to have it properly oriented but are also an integral part of the inserting machine.
Examples of devices which turn flat articles are shown in U.S. Pat. Nos. 4,726,461 issued Feb. 23, 1988 to J. Pokrinchak and 4,928,807 issued May 29, 1990 to D. Auerbach, both of which patents are assigned to the assignee of the present invention.
It is known to change the direction of travel for flat articles without changing the orientation of the articles, i.e., without rotating or turning the articles. It is also known that for a one stage right angle change in direction the articles must be stopped in one direction before being conveyed in the right angled direction. Such a device is described in U.S. Pat. No. 4,909,374 issued Mar. 20, 1990 to M. Skrypalle and assigned to the assignee of the present invention.
It is also known that a right angle change of direction for flat articles can be achieved in two or more stages by the use of deflection rollers which change the direction of travel by forty-five degrees (45.degree.) or less at each stage. Such an apparatus and method used in a sorting machine is disclosed in U.S. Pat. No. 4,527,792 issued Jul. 9, 1985 to G. Burkhardt. The Burkhardt apparatus has several limitations which prevent it from being useable in an inserter machine. The apparatus is limited to changing the direction of travel from a path parallel to a long edge of the mailpiece to a path of travel parallel to the short edge thereof. Furthermore, for all sized mailpieces, the Burkhardt apparatus requires a side-justified line of travel along the first direction of travel so that the deflection rollers can engage the article at the right moment to achieve an accurate change in direction. Typically, in an inserter, the center line of travel of the mailpiece is fixed with the side guides being adjustable for handling various sized mailpieces.
Several improvements in the throughput of various upstream modules (such as feeders, accumulators and insert stations) have raised the expectation that the output of the inserter machine will keep up with such improvements. However, when the output is increased on inserters which including conventional turner devices, the turner devices are not maintaining the increased output rate. The turner devices are experiencing various problems when they are operated at higher speeds. For example, inserts are flying out of envelopes before the flap can be closed and turner components are malfunctioning.